Electron radiograph patient identification system

ABSTRACT

Method and apparatus for placing identification of a patient or other object on an x-ray picture produced on a dielectric receptor sheet by electron radiography. A system for providing a uniform charge on an identification zone of a dielectric receptor, and for discharging selected portions of the charged zone by contact with a photoconductor unit having selected portions thereof made conductive by radiation, with the selected portions providing the identification of the object. A roller mechanism and a flat plate mechanism for providing the contact between charged receptor and photoconductor unit. An optical system and a light emitting diode system for generating the identification pattern.

United States Patent Allan et al.

ELECTRON RADIOGRAPH PATIENT IDENTIFICATION SYSTEM Inventors: Frank V.Allan; Murray S.

Welkowsky, both of Los Angeles, Calif.

Assignee: Xonics, Inc., Van Nuys, Calif.

Filed: Dec. 10, 1973 Appl. No.: 423,408

11.8. CI. 250/315, 250/324 Int. Cl. G03b 41/16 Field of Search 250/315A, 476

IMAGING CHFVMSER Primary Examiner.lames W. Lawrence AssistantExaminerDavis L. Willis Attorney, Agent, or FirmHarris, Kern, Wallen &Tinsley 5 7] ABSTRACT Method and apparatus for placing identification ofa patient or other object on an x-ray picture produced on a dielectricreceptor sheet by electron radiography. A system for providing a uniformcharge on an identification zone of a dielectric receptor, and fordischarging selected portions of the charged zone by contact with aphotoconductor unit having selected portions thereof made conductive byradiation, with the selected portions providing the identification ofthe object. A roller mechanism and a flat plate mechanism for providingthe contact between charged receptor and photoconductor unit. An opticalsystem and a light emitting diode system for generating theidentification pattern.

13 Claims, 4 Drawing Figures 4 DATA T-CHRD 20 BACKGROUND OF THEINVENTION This invention relates to the creation of x-ray images withoutthe use of conventional x-ray film, sometimes referred to as electronradiography, such as the technique described in the copendingapplication of Muntz et al, Ser. No. 261,927, filed June 12, 1972,entitled Radiographic Systems with Xerographic Printing and now US. Pat.No. 3,774,029, and assigned to same assignee as the present application.

In such a system, a fluid, typically xenon gas, is used between spacedelectrodes in an imaging chamber to produce a photoelectric currentwithin that chamber as 'a function of x-rays entering the chamber. Thecurrent is collected on a dielectric receptor sheet, typically Mylar,placed on one of the electrodes, resulting in a latent electrostaticimage on the sheet. The latent image is then made visible byconventional xerographic development techniques.

The electron radiographic system is particularly well suited for makingmedical x-rays and present day medical x-ray systems usually requireincorporation of an arrangement for placing patient identification onthe resultant picture. Typically the identification information must beplaced into the x-ray system prior to making the x-ray exposure, thesystem having an interlock which prevents exposure until theidentification information has been inserted. Actual production of thedata pattern on the picture film or receptor may occur prior, during orsubsequent to the x-ray exposure.

In the conventional system utilizing photographic film, lead charactersare placed on the imaging cassette, resulting in clear characters on ablack background in the exposed film. Some alternative arrangementsutilize punched cards or other selectivelytransparent devices which relyupon the light sensitive properties of the film.

However, the electron radiography system is insensitive to light andnone of the conventional systems using light or x-ray radiation toexpose the film can be utili'zed for object identification. One suchsystem for placing markings on x-ray film is shown in US. Pat. No.3,683,182.

US. Pat. No. 3,244,546 discloses a system for producing characters in aconventional xerographic printer. A data strip is embossed with thedesired characters and this embossed strip is brought into contact withthe electrostatic charged surface of the drum. The drum is discharged inthe regions contacted by the embossed strip, with the raised portionsout of contact with the drum. The drum surface is then bathed with tonerparticles which adhere in the charged regions, and this toner image istransferred to a web in the conventional manner thereby printing thedata on the web.

US. Pat. No. 3,472,136 shows an alternative system for generating datacharacters on a xerographic printer drum. A plurality of belts aremounted side-by-side, each belt carrying a series of the desiredcharacters,

witha data word being produced by appropriately positioning each belt.Light is directed through transparent characters onto the photoconductordrum after which the toner particles are applied to the drum and thetoner image is transferred to the web.

Electrostatic type printing systems utilizing stencils for the tonerpowder are shown in US. Pat. Nos. 3,504,624; 3,635,157; and 3,638,566.

All of these prior art devices require some form of mechanical charactergenerator with type or stencils or wheels or belts which must beindividually manipulated by the individual operating the x-rayapparatus. Also, the belt, wheel and stencil styles are inherentlylimited in the characters available, placing an undue restriction on thetype of data which can be used for identification purposes.

SUMMARY OF THE INVENTION The present invention provides objectidentification in an electron radiographic system using an opticalarrangement which in its preferred embodiment can provide any form ofidentification including characters and pictorial representations, allfrom a previously prepared data card. The object identification systemof the present invention does not require any character manipulation bythe operator, who merely inserts the data card into the x-ray machineprior to exposure. In one alternative embodiment, the operator may keyin the identification data prior to exposure.

The identification carrying zone of the dielectric receptor issubstantially uniformly charged and is then selectively discharged in apattern corresponding to the identification data. Selective discharge isachieved by contacting the dielectric receptor with a photoconductorunit which is made selectively conductive by an optical system directingradiation to the photoconductor unit. The selective discharge may beperformed prior, during or subsequent to the x-ray exposure. After theidentification data has been produced on the receptor and after thex-ray exposure, the receptor is then ready for developing of the latentelectrostatic image in the conventional manner.

BRIEF DESCRIPTION OF THE DRAWING emitting diodes; and

FIG. 4 illustrates an alternative embodiment of the photoconductor unitof FIG. 1 incorporating a drum.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The apparatus of FIG. 1includes a charging station 10, an imaging chamber 11 with x-ray tube12, an identification station 13, and a developing chamber 14. At thecharging station 10, a sheet of dielectric receptor 20 rests on abacking plate 21. The backing plate has an electrically conducting uppersurface and typically is made of metal. A portion 22 of the backingplate is electrically insulated from the remainder of the plate 21, asshown in FIG. 2. The dielectric receptor 20 has an electricallyconducting lower surface in contact with the backing plate. Theconducting surface may be obtained in various ways, as by means of apeelable layer of conducting paper or a bonded layer of a transparentconducting plastic or a film of a conducting liquid.- While theconducting surface of the dielectric receptor has a conductivity highrelative to that of the opposite surface on which the electrostaticcharge image is formed, the conducting surface actually is a poorelectrical conductor when compared to a metal, typically having aresistivity in the order of to l0 ohms/- square.

An electrostatic charge is produced on the receptor as by means of aconventional corona generator unit 24 which may be the size of thereceptor or which may be smaller, with the unit 24 moving relative tothe receptor to cover the entire surface. The major portion of thebacking plate 21 is connected to circuit ground and the portion 22 isconnected to a dc source 25. With this configuration, the receptor issubstantially uniformly discharged to neutral or zero potential all overexcept for the zone overlying the backing plate portion 22. This zone ofthe receptor is substantially uniformly charged to a potential dependentupon the potential of the source 25 and the potential of the coronagenerator unit 24, typically in the order of a few hundred volts.

The receptor with the charged zone is now ready for insertion into theimaging chamber 11 where the electrostatic image of the patient or otherobject is produced in the manner described in the aforesaid copendingapplication. After exposure, the receptor is moved to the identificationstation 13 which includes a conductive backing plate and aphotoconductor unit 31. The backing plate 30 has an electricalconducting upper surface for contacting the conducting surface of thereceptor, and typically it is made of sheet metal. The photo conductorunit 31 comprises a plate of a dielectric photoconductive material withan electrical conducting upper surface 32. The photoconductive materialmay be one of the conventional materials available, and the conductinglayer 32 may be a thin transparent metallic film. A mechanism indicatedgenerally at 34 serves to move the unit 31 downward into contact withthe receptor 20 and upward away from the receptor. The unit 31 is thesize of the portion 22 and the components are arranged so that the unit31 engages the charged zone of the receptor. The backing plate 30 andthe conducting surface 32 are electrically interconnected, as by beingconnected to circuit ground.

An optical system provides for directing radiation in a predeterminedpattern onto the photoconductor unit 31, with the pattern providing theidentification information for the object x-rayed. Radiation, typicallyvisible light, is directed from a source onto a data card 41, which isimaged at the unit 31 through the transparent electrical conductingupper surface, with lenses 43 as needed. The identification informationmay be typed, written or otherwise placed on the data card as desired,with the radiation pattern arriving at the photoconductor unit being afunction of the information on the data card. The regions of thephotoconductor unit receiving the radiation becomeelectricallyconductive. When the photoconductor unit with the electrical conductivepattern therein is brought into contact with the charged zone of thereceptor, the receptor is locally discharged through the conductingphotoconductive material, the conducting layer 32 and the backing plate30, leaving a charge pattern corresponding to the pattern on the datacard.

The photoconductor unit 31 is moved out of engagement with the receptorand the receptor is moved onto the developing chamber 14. The receptoris bathed in toner particles which adhere to the charged portions andproduce the visible image, including the identification 45.

The sequence of operation illustrated in H0. 1 may be varied as desired.As example, the zone on the receptor may be charged and theidentification discharge pattern produced prior to x-ray exposure.Alternatively the x-ray exposure may be made, after which the zone ischarged and selectively discharged. Of course. the zone must beprotected from x-ray radiation in the imaging chamber if it is chargedprior to x-ray exposure. At the identification station, the image of thedata card may be projected onto the photoconductor unit at the time ofengagement with the receptor or prior to engagement, since thephotoconductive material remains conductive for a period of time afterexposure.

An alternative embodiment of the photoconductor unit which utilizeslight emitting elements such as light emitting diodes for the opticalsystem is illustrated in FIG. 3. An array of light emitting diodes 48may be positioned directly on the photoconductive material of thephotoconductor unit. The light emitting elements 48 may be utilized toprovide any desired image, typically a plurality of seven bar numbers.The patient identification or other data may be introduced into a dataprocessor 49 via a keyboard 50, with the data processor determiningwhich elements 48 are to be energized to generate the desiredinformation. The energized elements 48 make the corresponding portionsof the photoconductor unit 32 electrically conductive, permittingoperation in the manner described in conjuction with the embodiment ofFIG. 1.

1n the alternative embodiment of FIG. 4, a drum 60 is utilized in placeof the photoconductor unit plate 31. The drum has an outer layer 61 ofphotoconductive material and an inner electrical conducting layer 62connected to circuit ground by suitable means such as resilient wipers(not shown). The photoconductive material of the drum is made locallyconductive by an optical system such as the described in conjuction withthe embodiment of P10. 1. The drum configuration is particularly suitedfor use with a system where the receptor moves through theidentification station without stopping, with the drum in rollingcontact with the re ceptor. The operation of the embodiment of FIG. 4may be the same as the embodiment of FIG. 1.

We claim:

1. A method of placing object identification on an x-ray picture formedon a dielectric receptor by electronradiography, including the steps of:

producing an electrostatic charge image on a dielectric receptor byexposing the object to x-ray radiation;

producing a substantially uniform electrostatic charge on a zone of thedielectric receptor; contacting the receptor at the charged zone by aphotoconductor with the receptor and photoconductor having contiguousnonconducting surfaces and spaced interconnected conducting surfaces;directing radiation to the photoconductor in a pattern which identifiesthe object and making selected portions of the photoconductorconductive;

discharging the portions of the charged zone of the receptor in contactwith said selected photoconductor portions; and

developing a visual image on the receptor corresponding to the chargesthereon.

2. A method as defined in claim 1 including simultaneously producing thesubstantially uniform electrostatic charge on the zone of the dielectricreceptor and a substantially neutral charge on the remainder of thereceptor prior to the exposure step.

3. A method as defined in claim 1 wherein said zone is charged prior tosaid exposure.

4. A method as defined in claim 1 wherein said zone is chargedsubsequent to said exposure.

5. A method as defined in claim 1 wherein the radiation is directed tothe photoconductor while the photoconductor is in contact with thereceptor.

6. A method as defined in claim 1 wherein radiation is directed to thephotoconductor prior to contacting the receptor.

7. Apparatus for providing object identification on an x-ray pictureformed on a dielectric receptor by electronradiography, including incombination:

first means for producing a substantially uniform electrostatic chargeon a zone of a first nonconducting surface of a dielectric receptorhaving a second conducting surface;

a photoconductor unit having a first nonconducting suface and a secondconducting surface;

second means for interconnecting the second surfaces;

third means for bringing the first surfaces into contact with eachother; an

fourth means for directing radiation to said photoconductor unit in apredetermined pattern making predetermined portions of saidphotoconductor unit conductive, with the contact of said first surfacesdischarging said charged zone in the predetermined pattern. 8. Apparatusas defined in claim 7 wherein said photoconductor unit includes a drumwith a photoconductive layer, and said third means includes means forrolling said drum along the receptor.

9. Apparatus as defined in claim 7 wherein said photoconductor unitincludes a plate with a photoconductive layer, and said third meansincludes means for moving said plate and receptor toward and away fromeach other.

10. Apparatus as defined in claim 7 wherein said fourth means includes aradiation source and an optical system for directing radiation from saidsource to a pattern defining element and then to said photoconductorunit.

11. Apparatus as defined in claim 7 wherein said fourth means includesan array of radiation emitting elements positioned at saidphotoconductor unit and means for energizing selected radiation emittingelements in said predetermined pattern.

12. Apparatus as defined in claim 7 wherein said first means includes;

a corona generator; a conducting backing plate for supporting adielectric receptor spaced from said generator, said plate having firstand second sections electrically insulated from each other;

means for connecting said first section to circuit ground; and

means for connecting said section to a dc potential.

13. Apparatus as defined in claim 7 wherein said second conductingsurface of said photoconductor unit is transparent to said radiation.

1. A method of placing object identification on an x-ray picture formed on a dielectric receptor by electronradiography, including the steps of: producing an electrostatic charge image on a dielectric receptor by exposing the object to x-ray radiation; producing a substantially uniform electrostatic charge on a zone of the dielectric receptor; contacting the receptor at the charged zone by a photoconductor with the receptor and photoconductor having contiguous nonconducting surfaces and spaced interconnected conducting surfaces; directing radiation to the photoconductor in a pattern which identifies the object and making selected portions of the photoconductor conductive; discharging the portions of the charged zone of the receptor in contact with said selected photoconductor portions; and developing a visual image on the receptor corresponding to the charges thereon.
 2. A method as defined in claim 1 including simultaneously producing the substantially uniform electrostatic charge on the zone of the dielectric receptor and a substantially neutral charge on the remainder of the receptor prior to the exposure step.
 3. A method as defined in claim 1 wherein said zone is charged prior to said exposure.
 4. A method as defined in claim 1 wherein said zone is charged subsequent to said exposure.
 5. A method as defined in claim 1 wherein the radiation is directed to the photoconductor while the photoconductor is in contact with the receptor.
 6. A method as defined in claim 1 wherein radiation is directed to the photoconductor prior to contacting the receptor.
 7. Apparatus for providing object identification on an x-ray picture formed on a dielectric receptor by electronradiography, including in combination: first means for producing a substantially uniform electrostatic charge on a zone of a first nonconducting surface of a dielectric receptor having a second conducting surface; a photoconductor unit having a first nonconducting suface and a second conducting surface; second means for interconnecting the second surfaces; third means for bringing the first surfaces into contact with each other; an fourth means for directing radiation to said photoconductor unit in a predetermined pattern making predetermined portions of said photoconductor unit conductive, with the contact of said first surfaces discharging said charged zone in the predetermined pattern.
 8. Apparatus as defined in claim 7 wherein said photoconductor unit includes a drum with a photoconductive layer, and said third means includes means for rolling said drum along the receptor.
 9. Apparatus as defined in claim 7 wherein said photoconductor unit includes a plate with a photoconductive layer, and said third means includes means for moving said plate and receptor toward and away from each other.
 10. Apparatus as defined in claim 7 wherein said fourth means includes a radiation source and an optical system for directing radiation from said source to a pattern defining element and then to said photoconductor unit.
 11. Apparatus as defined in claim 7 wherein said fourth means includes an array of radiation emitting elements positioned at said photoconductor unit and means for energizing selected radiation emitting elements in said predetermined pattern.
 12. Apparatus as defined in claim 7 wherein said first means includes; a corona generator; a conducting backing plate for supporting a dielectric receptor spaced from said generator, said plate having first and second sections electrically insulated from each other; means for connecting said first section to circuit ground; and means for connecting said section to a dc potential.
 13. Apparatus as defined in claim 7 wherein said second conducting surface of said photoconductor unit is transparent to said radiation. 